U.S. patent number 6,248,067 [Application Number 09/246,661] was granted by the patent office on 2001-06-19 for analyte sensor and holter-type monitor system and method of using the same.
This patent grant is currently assigned to MiniMed Inc.. Invention is credited to James D. Causey, III, Paul H. Kovelman, John J. Mastrototaro, Richard E. Purvis.
United States Patent |
6,248,067 |
Causey, III , et
al. |
June 19, 2001 |
Analyte sensor and holter-type monitor system and method of using
the same
Abstract
A Holter-type monitor system includes a remotely located data
receiving device, an analyte sensor for producing signal indicative
of a characteristic of a user, and a Holter-type recording device.
The Holter-type recording device includes a housing, a sensor
connector, a processor, and a data port. The sensor connector
receives the produced signals from the analyte sensor. The
processor is coupled to the sensor connector and stores the signals
from the analyte sensor for delivery to the remotely located data
receiving device. The recording device is coupled to the processor
for downloading the stored signals to the remotely located data
receiving device. The data receiving device may be a characteristic
monitor, a data receiver that provides data to another device, an
RF programmer, a medication delivery device (such as an infusion
pump), or the like.
Inventors: |
Causey, III; James D. (Simi
Valley, CA), Kovelman; Paul H. (Simi Valley, CA), Purvis;
Richard E. (Pasadena, CA), Mastrototaro; John J. (Los
Angeles, CA) |
Assignee: |
MiniMed Inc. (Northridge,
CA)
|
Family
ID: |
22931651 |
Appl.
No.: |
09/246,661 |
Filed: |
February 5, 1999 |
Current U.S.
Class: |
600/365; 128/903;
600/347 |
Current CPC
Class: |
A61B
5/0002 (20130101); A61B 5/14532 (20130101); A61B
5/1473 (20130101); A61B 2560/0214 (20130101); Y10S
128/903 (20130101) |
Current International
Class: |
A61B
5/00 (20060101); A61B 005/00 () |
Field of
Search: |
;600/300,301,309,310,316,322,345,347,364,365 ;128/903,904 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0880936 |
|
Dec 1998 |
|
EP |
|
9401039 |
|
Jan 1994 |
|
WO |
|
9956613 |
|
Nov 1999 |
|
WO |
|
Other References
T Arai, et al., "A Portable Transcutaneous Blood Glucose Monitoring
System Using Non-Invasive Collection of Suction Effusion Fluid from
Skin", IEEE, pp. 812-813 (1994)..
|
Primary Examiner: Winakur; Eric F.
Attorney, Agent or Firm: MiniMed Inc.
Claims
What is claimed is:
1. A Holter-type monitor system for monitoring a glucose
characteristic of a user, the system comprising:
a remotely located data receiving device;
an analyte sensor for measuring glucose in interstitial fluid and
for producing a signal indicative of the glucose characteristic of
the user; and
a Holter-type recording device including:
a housing;
a sensor connector coupled to the housing and that is connectable
to the analyte sensor to receive the produced signals from the
analyte sensor;
a processor including a memory coupled to the sensor connector to
store the signals from the analyte sensor for delivery to the
remotely located data receiving device; and
data downloading means coupled to the processor for downloading the
stored signals to the remotely located data receiving device,
wherein the Holter-type recording device initializes the analyte
sensor when the analyte sensor is connected to the Holter-type
recording device.
2. A Holter-type monitor system according to claim 1, wherein the
Holter-type recording device downloads the stored signals via the
data downloading means by radio frequencies.
3. A Holter-type monitor system according to claim 1, wherein the
Holter-type recording device downloads the stored signals via the
data downloading means by optical frequencies.
4. A Holter-type monitor system according to claim 1, wherein the
analyte sensor is an implantable analyte sensor, and wherein the
sensor connector of the Holter-type recording device includes a
cable that is connectable to the implantable analyte sensor.
5. A Holter-type monitor system according to claim 4, wherein the
implantable analyte sensor is configured for a direct wired
connection to a characteristic monitor using a standardized
connector, and wherein the sensor connector of the Holter-type
recording device is formed to connect to the configured implantable
analyte sensor using the standardized connector.
6. A Holter-type monitor system according to claim 1, wherein the
analyte sensor is a percutaneous analyte sensor, and wherein the
sensor connector of the Holter-type recording device includes a
cable that is connected to the percutaneous analyte sensor.
7. A Holter-type monitor system according to claim 6, wherein the
percutaneous analyte sensor is configured for a direct wired
connection to a characteristic monitor using a standardized
connector, and wherein the sensor connector of the Holter-type
recording device is formed to connect to the configured
percutaneous analyte sensor using the standardized connector.
8. A Holter-type monitor system according to claim 1, wherein the
analyte sensor is an skin surface analyte sensor, and wherein the
sensor connector of the Holter-type recording device includes a
cable that is connectable to the skin surface analyte sensor.
9. A Holter-type monitor system according to claim 8, wherein the
skin surface analyte sensor is configured for a direct wired
connection to a characteristic monitor using a standardized
connector, and wherein the sensor connector of the Holter-type
recording device is formed to connect to the configured skin
surface analyte sensor using the standardized connector.
10. A Holter-type monitor system according to claim 1, wherein the
data receiving device is a data receiver that also provides data to
another device.
11. A Holter-type monitor system according to claim 1, wherein the
data receiving device is a characteristic monitor.
12. A Holter-type monitor system according to claim 1, wherein the
sensor connector applies power to the analyte sensor.
13. A Holter-type monitor system according to claim 1, wherein the
interstitial fluid for contact with the analyte sensor is obtained
using invasive techniques.
14. A Holter-type monitor system according to claim 1, wherein the
analyte sensor initialization includes using stabilization.
15. A Holter-type monitor system according to claim 1, wherein the
analyte sensor initialization includes using calibration.
16. A Holter-type monitor system according to claim 1, wherein the
analyte sensor is an enzyme based glucose sensor.
17. A Holter-type monitor system according to claim 1, wherein the
Holter-type recording device includes an optical indicator.
18. A Holter-type monitor system for monitoring a glucose
characteristic of a user, the system comprising:
a remotely located data receiving device;
an analyte sensor for measuring glucose in interstitial fluid for
producing a signal indicative of the glucose characteristic of the
user; and
a Holter-type recording device including:
a housing;
a sensor connector coupled to the housing and that is connectable
to the analyte sensor to receive the produced signals from the
anayte sensor;
a processor including a memory coupled to the sensor connector to
store the signals from the analyte sensor for delivery to the
remotely located data receiving device; and
data downloading means coupled to the processor for downloading the
stored signals to the remotely located data receiving device,
wherein the Holter-type recording device further includes a
receiver to receive data and instructions from the data receiving
device, and
wherein the Holter-type recording device initializes the analyte
sensor when the analyte sensor is connected to the Holter-type
recording device.
19. A Holter-type monitor system for monitoring a glucose
characteristic of a user, the system comprising:
a remotely located data receiving device;
an analyte sensor for measuring glucose in interstitial fluid for
producing a signal indicative of the glucose characteristic of the
user; and
a Holter-type recording device including:
a housing;
a sensor connector coupled to the housing and that is connectable
to the analyte sensor to receive the produced signals from the
analyte sensor;
a processor including a memory coupled to the sensor connector to
store the signals from the analyte sensor for delivery to the
remotely located data receiving device; and
data downloading means coupled to the processor for downloading the
stored signals to the remotely located data receiving device,
wherein the data receiving device is an RF programmer, and
wherein the Holter-type recording device initializes the analyte
sensor when the analyte sensor is connected to the Holter-type
recording device.
20. A Holter-type monitor system for monitoring a glucose
characteristic of a user, the system comprising:
a remotely located data receiving device;
an analyte sensor for measuring glucose in interstitial fluid for
producing a signal indicative of the glucose characteristic of the
user; and
a Holter-type recording device including:
a housing;
a sensor connector coupled to the housing and that is connectable
to the analyte sensor to receive the produced signals from the
analyte sensor;
a processor including a memory coupled to the sensor connector to
store the signals from the analyte sensor for delivery to the
remotely located data receiving device; and
data downloading means coupled to the processor for downloading the
stored signals to the remotely located data receiving device,
wherein the data receiving device is a medication delivery device,
and
wherein the Holter-type recording device initializes the analyte
sensor when the analyte sensor is connected to the Holter-type
recording device.
21. A Holter-type monitor system for monitoring a glucose
characteristic of a user, the system comprising:
a remotely located data receiving device;
an analyte sensor for measuring glucose in interstitial fluid for
producing a signal indicative of the glucose characteristic of the
user; and
a Holter-type recording device including:
a housing;
a sensor connector coupled to the housing and that is connectable
to the analyte sensor to receive the produced signals from the
analyte sensor;
a processor including a memory coupled to the sensor connector to
store the signals from the analyte sensor for delivery to the
remotely located data receiving device; and
data downloading means coupled to the processor for downloading the
stored signals to the remotely located data receiving device,
wherein the data receiving device is an infusion pump, and
wherein the Holter-type recording device initializes the analyte
sensor when the analyte sensor is connected to the Holter-type
recording device.
22. A Holter-type monitor system for monitoring a glucose
characteristic of a user, the system comprising:
a remotely located data receiving device;
an analyte sensor for measuring glucose in interstitial fluid for
producing a signal indicative of the glucose characteristic of the
user; and
a Holter-type recording device including:
a housing;
a sensor connector coupled to the housing and that is connectable
to the analyte sensor to receive the produced signals from the
analyte sensor;
a processor including a memory coupled to the sensor connector to
store the signals from the analyte sensor for delivery to the
remotely located data receiving device; and
data downloading means port coupled to the processor for
downloading the stored signals to the remotely located data
receiving device,
and further including a separate glucose detection device to
provide calibration data, and wherein all processed signals
received by the data receiving device are post processed with the
calibration date, and
wherein the Holter-type recording device initializes the analyte
sensor when the analyte sensor is connected to the Holter-type
recording device.
23. A Holter-type recording device for use in a system with a
remotely located data processing device and an analyte sensor for
measuring glucose levels in interstitial fluid and for producing a
signal indicative of a glucose characteristic of a user, the
Holter-type recording device comprising:
a housing;
a sensor connector coupled to the housing and that is connectable
to the analyte sensor to receive the produced signal from the
analyte sensor;
a processor including a memory coupled to the sensor connector to
store the signal from the analyte sensor for delivery to the
remotely located data processing device; and
data downloading means coupled to the processor for downloading the
stored signals to the remotely located data processing device,
wherein the Holter-type recording device initializes the analyte
sensor when the analyte sensor is connected to the Holter-type
recording device.
24. A Holter-type recording device according to claim 23, wherein
the data downloading means downloads the stored signals via the
data port by radio frequencies.
25. A Holter-type recording device according to claim 23, wherein
the analyte sensor is an implantable analyte sensor, and wherein
the sensor connector of the Holter-type recording device includes a
cable that is connectable to the implantable analyte sensor.
26. A Holter-type recording device according to claim 25, wherein
the implantable analyte sensor is configured for a direct wired
connection to a characteristic monitor using a standardized
connector, and wherein the sensor connector of the Holter-type
recording device is formed to connect to the configured implantable
analyte sensor using the standardized connector.
27. A Holter-type recording device according to claim 23, wherein
the analyte sensor is a percutaneous analyte sensor, and wherein
the sensor connector of the Holter-type recording device includes a
cable that is connectable to the percutaneous analyte sensor.
28. A Holter-type recording device according to claim 27, wherein
the percutaneous analyte sensor is configured for a direct wired
connection to a characteristic monitor using a standardized
connector, and wherein the sensor connector of the Holter-type
recording device is formed to connect to the configured
percutaneous analyte sensor using the standardized connector.
29. A Holter-type recording device according to claim 23, wherein
the analyte sensor is an skin surface analyte sensor, and wherein
the sensor connector of the Holter-type recording device includes a
cable that is connectable to the skin surface analyte sensor.
30. A Holter-type recording device according to claim 29, wherein
the skin surface analyte sensor is configured for a direct wired
connection to a characteristic monitor using a standardized
connector, and wherein the sensor connector of the Holter-type
recording device is formed to connect to the configured skin
surface analyte sensor using the standardized connector.
31. A Holter-type recording device according to claim 23, further
including a receiver to receive data and instructions from the data
processing device.
32. A Holter-type recording device according to claim 23, wherein
the housing includes a bio-compatible adhesive adapted to secure
the housing to a skin surface of the user.
33. A Holter-type recording device according to claim 32, wherein
the bio-compatible adhesive is an anti-bacterial adhesive.
34. A Holter-type recording device according to claim 23, wherein
the housing is secured to a skin surface of the user by an adhesive
overdressing.
35. A Holter-type recording device according to claim 23, wherein
the housing is less than about 1.5 inches in diameter by 0.25
inches thick.
36. A Holter-type recording device according to claim 23, wherein
the housing is resistant to fluids when immersed in a fluid.
37. A Holter-type recording device according to claim 23, wherein
the Holter-type recording device is operable in a temperature range
of 0.degree. C. to 50.degree. C.
38. A Holter-type recording device according to claim 23, wherein
the Holter-type recording device includes a power source that has
an operable life of at least 2 weeks.
39. A Holter-type recording device according to claim 23, wherein
the sensor connector applies power to the analyte sensor.
40. A Holter-type recording device according to claim 23, wherein
the Holter-type recording device is activated by detection of a
connection of the analyte sensor to the sensor connector.
41. A Holter-type recording device according to claim 23, wherein
the Holter-type recording device includes an optical indicator.
Description
FIELD OF THE INVENTION
This invention relates to Holter-type monitor systems and, in
particular embodiments, to devices and methods for Holter-type
monitoring of an analyte sensor to determine a characteristic of a
body.
BACKGROUND OF THE INVENTION
Over the years, bodily characteristics have been determined by
obtaining a sample of bodily fluid. For example, diabetics often
test for blood glucose levels. Traditional blood glucose
determinations have utilized a painful finger prick using a lancet
to withdraw a small blood sample. This results in discomfort from
the lancet as it contacts nerves in the subcutaneous tissue. The
pain of lancing and the cumulative discomfort from multiple needle
pricks is a strong reason why patients fail to comply with a
medical testing regimen used to determine a change in
characteristic over a period of time. Although non-invasive systems
have been proposed, or are in development, none to date have been
commercialized that are effective and provide accurate results. In
addition, all of these systems are designed to provide data at
discrete points and do not provide continuous data to show the
variations in the characteristic between testing times.
A variety of implantable electrochemical sensors have been
developed for detecting and/or quantifying specific agents or
compositions in a patient's blood. For instance, glucose sensors
have been developed for use in obtaining an indication of blood
glucose levels in a diabetic patient. Such readings are useful in
monitoring and/or adjusting a treatment regimen which typically
includes the regular administration of insulin to the patient.
Thus, blood glucose readings improve medical therapies with
semi-automated medication infusion pumps of the external type, as
generally described in U.S. Pat. Nos. 4,562,751; 4,678,408; and
4,685,903; or automated implantable medication infusion pumps, as
generally described in U.S. Pat. No. 4,573,994, which are herein
incorporated by reference. Typical thin film sensors are described
in commonly assigned U.S. Pat. Nos. 5,390,671; 5,391,250;
5,482,473; and 5,586,553 which are incorporated by reference
herein. See also U.S. Pat. No. 5,299,571. However, the monitors for
these continuous sensors provide alarms, updates, trend information
and require sophisticated hardware to allow the user to program the
monitor, calibrate the sensor, enter data and view data in the
monitor and to provide realtime feedback to the user. This
sophisticated hardware makes it most practical for users that
require continuous monitoring with feedback to maintain tight
control over their conditions. In addition, these systems require
the user to be trained in their use, even if to be worn for short
periods of time to collect medical data which will be analyzed
later by a doctor.
Doctors often need continuous measurements of a body parameter over
a period of time to make an accurate diagnosis of a condition. For
instance, Holter monitor systems are used to measure the EKG of a
patient's heart over a period of time to detect abnormalities in
the heart beat of the patient. Abnormalities detected in this
manner may detect heart disease that would otherwise go undetected.
These tests, while very useful are limited to monitoring of
bio-mechanical physical changes in the body, such as a heart beat,
respiration rate, blood pressure or the like.
SUMMARY OF THE DISCLOSURE
It is an object of an embodiment of the present invention to
provide an improved Holter-type monitor system with an analyte
sensor set and monitor connection device, which obviates for
practical purposes, the above mentioned limitations.
According to an embodiment of the invention, a Holter-type monitor
system includes a remotely located data receiving device, an
analyte sensor for producing signal indicative of a characteristic
of a user, and a Holter-type recording device. In preferred
embodiments, the Holter-type recording device includes a housing, a
sensor connector, a processor, and a data port. The sensor
connector receives the produced signals from the analyte sensor.
The processor is coupled to the sensor connector and stores the
signals from the analyte sensor for delivery to the remotely
located data receiving device. The download data port of the
Holter-type recording device is coupled to the processor for
downloading the stored signals to the remotely located data
receiving device through the data port. In preferred embodiments,
the data receiving device is a characteristic monitor. However, in
other embodiments, the data receiving device is a data receiver
that provides data to another device, an RF programmer, a
medication delivery device (such as an infusion pump), or the like.
In particular embodiments, the data port of the Holter-type
recording device downloads the stored signals by radio frequencies,
infrared emissions, or the like. Additional embodiments may include
data storage memory and interface controls.
In particular embodiments, the analyte sensor is an implantable,
percutaneous or skin surface analyte sensor, and the sensor
connector of the Holter-type recording device includes a cable that
is connected to the implantable, percutaneous or skin surface
analyte sensor. Also, the analyte sensor can be configured for a
wired connection to a characteristic monitor, and the sensor
connector of the Holter-type recording device is formed to connect
to the configured analyte sensor. Still further embodiments of the
Holter-type recording device include a receiver to receive data and
instructions from the remotely located data receiving device, or
the like.
Embodiments of the Holter-type recording device may include a
bio-compatible adhesive to secure the housing to a skin surface of
the user. Preferably, the housing of the Holter-type recording
device is less than about 1.5 inches in diameter by 0.25 inches
thick. In addition, the housing is resistant to fluids when
immersed in a fluid, and operable in a temperature range of
0.degree. C. to 50.degree. C. The Holter-type recording device may
also include a power source that has an operable life of at least 2
weeks.
Other features and advantages of the invention will become apparent
from the following detailed description, taken in conjunction with
the accompanying drawings which illustrate, by way of example,
various features of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
A detailed description of embodiments of the invention will be made
with reference to the accompanying drawings, wherein like numerals
designate corresponding parts in the several figures.
FIG. 1 is a is a perspective view illustrating a subcutaneous
sensor insertion set and Holter-type monitor device embodying the
novel features of the invention;
FIG. 2 is an enlarged longitudinal vertical section taken generally
on the line 2--2 of FIG. 1;
FIG. 3 is an enlarged longitudinal sectional of a slotted insertion
needle used in the insertion set of FIGS. 1 and 2;
FIG. 4 is an enlarged transverse section taken generally on the
line 4--4 of FIG. 3;
FIG. 5 is an enlarged transverse section taken generally on the
line 5--5 of FIG. 3;
FIG. 6 is an enlarged fragmented sectional view corresponding
generally with the encircled region 6 of FIG. 2; and
FIG. 7 is an enlarged transverse section taken generally on the
line 7--7 of FIG. 2.
FIG. 8 is a simplified block diagram of a Holter-type monitoring
device in accordance with an embodiment of the present
invention.
FIG. 9 is a perspective view of a Holter-type monitor device and a
download activation device in accordance the embodiment shown in
FIG. 8.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in the drawings for purposes of illustration, the
invention is embodied in a Holter-type monitor system coupled to a
subcutaneous implantable analyte sensor set to provide continuous
data recording of the sensor readings for a period of time. The
recorded data then being later downloaded to another data
processing device to determine body characteristic data over a
period of time. In preferred embodiments of the present invention,
the analyte sensor set and Holter-type monitor system are for
determining glucose levels in the blood and/or bodily fluids of the
user without the use of, or necessity of, complicated monitoring
systems that require user training and interaction. However, it
will be recognized that further embodiments of the invention may be
used to determine the levels of other analytes or agents,
characteristics or compositions, such as hormones, cholesterol,
medications concentrations, viral loads (e.g., HIV), or the like.
In other embodiments, the Holter-type monitor system may also
include the capability to be programmed to take data at specified
time intervals or calibrated using an initial data input received
from an external device. The Holter-type monitor system and analyte
sensor are primarily adapted for use in subcutaneous human tissue.
However, still further embodiments may be placed in other types of
tissue, such as muscle, lymph, organ tissue, veins, arteries or the
like, and used in animal tissue. The analyte sensors may be
subcutaneous sensors, transcutaneous sensors, percutaneous sensors,
sub-dermal sensors, skin surface sensors, or the like. Embodiments
may record sensor readings on an intermittent or continuous
basis.
The Holter-type monitor system 1, in accordance with a preferred
embodiment of the present invention includes a subcutaneous analyte
sensor set 10, and a Holter-type recorder 100. The subcutaneous
analyte sensor set 10 utilizes an electrode-type sensor, as
described in more detail below. However, in alternative
embodiments, the analyte sensor set may use other types of sensors,
such as chemical based, optical based or the like. In further
alternative embodiments, the sensors may be of a type that is used
on the external surface of the skin or placed below the skin layer
of the user. Preferred embodiments of a surface mounted analyte
sensor would utilize interstitial fluid harvested from the
skin.
The Holter-type recorder 100 generally includes the capability to
record and store data as it is received from the analyte sensor 10,
and then includes either a data port or wireless transmitter for
downloading the data to a data processor 200, computer,
communication station, or the like for later analysis and review.
However, in alternative embodiments, the Holter-type recorder 100
may include a receiver, bi-directional data port, or the like, to
facilitate two-way access between the Holter-type recorder 100 and
a data processor 200, computer, communication station, or the like,
for initial calibration and test of the analyte sensor set 10. The
data processor 200, computer, or the like, utilizes the recorded
data from the Holter-type recorder 100 to determine the
characteristic history. Still further embodiments of the
Holter-type recorder 100 have and use an input port for direct
(e.g., wired) connection to a programming or data readout device
and/or be used for calibration of the analyte sensor set 10.
Preferably, any port would be water proof (or water resistant) or
include a water proof removable cover. The Holter-type recorder can
transmit the data by wire, or wireless signals including infrared
frequencies, optical frequencies, audio frequencies, hyper-audio
frequencies, ultrasonic frequencies, RF frequencies, or the
like.
The purpose of the Holter-type monitor system 1 is to provide for
better data recording and testing for various patient conditions
utilizing continuous or near continuous data recording. In
alternative embodiments, the data recording may be on an
intermittent basis with the data being collected at predetermined
periods of time ranging from minutes to hours. In addition, it is
desired to utilize a relatively simple and inexpensive recording
device that does not require patient interaction and is easily
suited to just record sensor data. This obviates the need for an
elaborate monitoring device.
The Holter-type monitor system 1 also removes inconvenience by
separating the complicated monitoring process electronics into two
separate devices; a Holter-type recorder 100, which attaches to the
analyte sensor set 10; and a data processor 200, computer,
communication station, or the like, which contains the software and
programming instructions to download and evaluate data recorded by
the Holter-type recorder 100. This provides several advantages over
wire connected devices. For instance, the user can more easily
conceal the presence of the monitor system 1, since a wire will not
be visible (or cumbersome), with clothing. In addition, the use of
multiple components (e.g., recorder 100 and data processor 200,
computer, communication station, or the like) facilitates upgrades
or replacements, since one module, or the other, can be modified or
replaced without requiring complete replacement of the monitor
system 1. Further, the use of multiple components can improve the
economics of manufacturing, since some components may require
replacement on a more frequent basis, sizing requirements may be
different for each module, there may be different assembly
environment requirements, and modifications can be made without
affecting the other components.
The Holter-type recorder 100 takes raw analyte sensor data, such as
glucose data or the like, from the subcutaneous analyte sensor set
10 and stores it for later download to the data processor 200,
computer, communication station, or the like, which analyzes,
displays and logs the received glucose readings. Downloaded data
can be subjected to further detailed data analysis. In further
embodiments, the Holter-type monitor system 1 may be used in a
hospital environment or the like. Still further embodiments of the
present invention may include one or more buttons on the
Holter-type recorder 100 to record data and events for later
analysis, correlation, or the like. In addition, the Holter-type
recorder may include an on/off button for compliance with safety
standards and regulations to temporarily suspend transmissions or
recording. Further buttons could include a sensor on/off button to
conserve power and to assist in initializing the analyte sensor set
10. The Holter-type recorder 100 may also be combined with other
medical devices to combine other patient data through a common data
network and telemetry system. The system may also include a
separate glucose detection device (such as a meter or monitor) to
provide calibration data for the data recorded by the Holter-type
recorder 100. For instance, all downloaded data received by the
processing device, computer, or the like, are post processed with
the calibration data from the separate glucose detection
device.
As shown in FIGS. 1-7, an implantable subcutaneous analyte sensor
set 10 is provided for subcutaneous placement of a flexible sensor
12 (see FIG. 2), or the like, at a selected site in the body of a
user. The implantable analyte sensor set 10 includes a hollow,
slotted insertion needle 14, and a cannula 16. The needle 14 is
used to facilitate quick and easy subcutaneous placement of the
cannula 16 at the subcutaneous insertion site. The cannula 16
includes a sensing portion 18 of the sensor 12 to expose one or
more sensor electrodes 20 to the user's bodily fluids through a
window 22 formed in the cannula 16. After insertion, the insertion
needle 14 is withdrawn to leave the cannula 16 with the sensing
portion 18 and the sensor electrodes 20 in place at the selected
insertion site.
In preferred embodiments, the implantable subcutaneous analyte
sensor set 10 facilitates accurate placement of a flexible thin
film electrochemical sensor 12 of the type used for monitoring
specific blood parameters representative of a user's condition.
Preferably, the sensor 12 monitors blood glucose levels, and may be
used in conjunction with automated or semi-automated medication
infusion pumps of the external or implantable type as described in
U.S. Pat. Nos. 4,562,751; 4,678,408; 4,685,903 or 4,573,994, to
deliver insulin to a diabetic patient. However, other embodiments
may monitor other analytes to determine viral load, HIV activity,
bacterial levels, cholesterol levels, medication levels, or the
like.
Preferred embodiments of the flexible electrochemical sensor 12 are
constructed in accordance with thin film mask techniques to include
elongated thin film conductors embedded or encased between layers
of a selected insulative material such as polyimide film or sheet.
The sensor electrodes 20 at a tip end of the sensing portion 18 are
exposed through one of the insulative layers for direct contact
with patient blood, or other bodily fluids, when the sensor 12 is
subcutaneously placed at an insertion site. The sensing portion 18
is joined to a connection portion 24 (see FIG. 2) that terminates
in conductive contact pads, or the like, which are also exposed
through one of the insulative layers. In alternative embodiments,
other types of implantable analyte sensors, such as chemical based,
optical based, or the like, may be used.
As is known in the art, and illustrated schematically in FIG. 2,
the connection portion 24 and the contact pads are generally
adapted for a direct wired electrical connection to a suitable
sensor monitor for monitoring a user's condition in response to
signals derived from the sensor electrodes 20. Further description
of flexible thin film sensors of this general type are be found in
U.S. Pat. No. 5,391,250, entitled METHOD OF FABRICATING THIN FILM
SENSORS, which is herein incorporated by reference. The connection
portion 24 of the analyte sensor set 10 may be conveniently
connected electrically to the sensor monitor (not shown), a
Holter-type recorder 100, or a data processor 200, computer,
communication station, or the like, by a connector block 28 (or the
like) as shown and described in U.S. Pat. No. 5,482,473, entitled
FLEX CIRCUIT CONNECTOR, which is also herein incorporated by
reference. Thus, in accordance with embodiments of the present
invention, subcutaneous sensor sets 10 are configured or formed to
work with either a wired or a wireless recording system.
The sensor 12 is mounted in a mounting base 30 adapted for
placement onto the skin of a user. As shown, the mounting base 30
is a generally rectangular pad having an underside surface coated
with a suitable pressure sensitive adhesive layer 32, with a
peel-off paper strip 34 normally provided to cover and protect the
adhesive layer 32, until the sensor set 10 is ready for use. As
shown in FIGS. 1 and 2, the mounting base 30 includes upper and
lower layers 36 and 38, with the connection portion 24 of the
flexible sensor 12 being sandwiched between the layers 36 and 38.
The connection portion 24 has a forward section joined to the
sensing portion 18 of the sensor 12, which is folded angularly to
extend downwardly through a bore 40 formed in the lower base layer
38. In preferred embodiments, the adhesive layer 32 includes an
anti-bacterial agent to reduce the chance of infection; however,
alternative embodiments may omit the agent. In further alternative
embodiments, the mounting base may be other shapes, such as
circular, oval, hour-glass, butterfly or the like.
The insertion needle 14 is adapted for slide-fit reception through
a needle port 42 formed in the upper base layer 36 and further
through the lower bore 40 in the lower base layer 38. As shown, the
insertion needle 14 has a sharpened tip 44 and an open slot 46
which extends longitudinally from the tip 44 at the underside of
the needle 14 to a position at least within the bore 40 in the
lower base layer 36. Above the mounting base 30, the insertion
needle 14 may have a full round cross-sectional shape, and may be
closed off at a rear end of the needle 14. Further description of
the needle 14 and the sensor set 10 are found in U.S. Pat. No.
5,586,553, entitled "TRANSCUTANEOUS SENSOR INSERTION SET" and
co-pending U.S. patent application Ser. No. 08/871,831, entitled
`DISPOSABLE SENSOR INSERTION ASSEMBLY," which are herein
incorporated by reference.
The cannula 16 is best shown in FIGS. 6 and 7, and includes a first
portion 48 having partly-circular cross-section to fit within the
insertion needle 14 that extends downwardly from the mounting base
30. In alternative embodiments, the first portion 48 may be formed
with a solid core; rather than a hollow core. In preferred
embodiments, the cannula 16 is constructed from a suitable medical
grade plastic or elastomer, such as polytetrafluoroethylene,
silicone, or the like. The cannula 16 also defines an open lumen 50
in a second portion 52 for receiving, protecting and guideably
supporting the sensing portion 18 of the sensor 12. The cannula 16
has one end fitted into the bore 40 formed in the lower layer 38 of
the mounting base 30, and the cannula 16 is secured to the mounting
base 30 by a suitable adhesive, ultrasonic welding, snap fit or
other selected attachment method. From the mounting base 30, the
cannula 16 extends angularly downwardly with the first portion 48
nested within the insertion needle 14, and terminates slightly
before the needle tip 44. At least one window 22 is formed in the
lumen 50 near the implanted end 54, in general alignment with the
sensor electrodes 20, to permit direct electrode exposure to the
user's bodily fluid when the sensor 12 is subcutaneously
placed.
As shown in FIGS. 1 and 2, the Holter-type recorder 100 is coupled
to a subcutaneous analyte sensor set 10 by a cable 102 through a
connector 104 that is electrically coupled to the connector block
28 of the connector portion 24 of the subcutaneous analyte sensor
set 10. In alternative embodiments, the cable 102 may be omitted,
and the Holter-type recorder 100 may include an appropriate
connector (not shown) for direct connection to the connector
portion 24 of the subcutaneous analyte sensor set 10 or the
subcutaneous analyte sensor set 10 may be modified to have the
connector portion 24 positioned at a different location, such as
for example, the top of the subcutaneous sensor set 10 to
facilitate placement of the telemetered characteristic monitor
transmitter over the subcutaneous sensor set 10. This would
minimize the amount of skin surface covered or contacted by medical
devices, and tend to minimize potential electrical interference
induced by movement of the subcutaneous analyte sensor set 10
relative to the telemetered characteristic monitor transmitter 100.
In further alternative embodiments, the cable 102 and the connector
104 may be formed as add-on adapters to fit different types of
connectors on different types or kinds of sensor sets. The use of
adapters would facilitate adaptation of the Holter-type recorder
100 to work with a wide variety of sensor systems.
The Holter-type recorder 100 includes a housing 106 that supports a
printed circuit board 108, batteries 110, memory storage 112, and
the cable 102 with the connector 104. In preferred embodiments, the
housing 106 is formed from an upper case 114 and a lower case 116
that are sealed with an ultrasonic weld to form a waterproof (or
resistant) seal to permit cleaning by immersion (or swabbing) with
water, cleaners, alcohol or the like. In preferred embodiments, the
upper and lower case 114 and 116 are formed from a medical grade
plastic. However, in alternative embodiments, the upper case 114
and lower case 116 may be connected together by other methods, such
as snap fits, sealing rings, RTV (silicone sealant) and bonded
together, or the like, or formed from other materials, such as
metal, composites, ceramics, or the like. In preferred embodiments,
the housing 106 is disk or oval shaped. However, in alternative
embodiments, other shapes, such as hour glass, rectangular or the
like, may be used. Preferred embodiments of the housing 106 are
sized in the range of 1.5 inches squared by 0.25 inches thick to
minimize weight, discomfort and the noticeability of the
Holter-type recorder 100 on the body of the user. However, larger
or smaller sizes, such as 0.5 inches squared and 0.15 inches thick
or less, and 3.0 inches squared and 0.5 inches thick or more, may
be used.
As shown, the lower case 116 may have an underside surface coated
with a suitable pressure sensitive adhesive layer 118, with a
peel-off paper strip 120 normally provided to cover and protect the
adhesive layer 118, until the Holter-type recorder 100 is ready for
use. In preferred embodiments, the adhesive layer 118 includes an
anti-bacterial agent to reduce the chance of infection; however,
alternative embodiments may omit the agent. In further alternative
embodiments, the adhesive layer 118 may be omitted and the
Holter-type recorder 100 is secured to the body by other methods,
such as an adhesive overdressing, straps, belts, clips or the
like.
In preferred embodiments, the cable 102 and connector 104 are
similar to (but not necessarily identical to) shortened versions of
a cable and connector that are used to provide a standard wired
connection between the subcutaneous analyte sensor set 10 and a
sensor monitor. This allows the Holter-type recorder 100 to be used
with existing subcutaneous analyte sensor sets 10, and avoids the
necessity to re-certify the connector portion 24 of the
subcutaneous analyte sensor set 10 for use with a Holter-type
recorder 100. The cable 102 should also include a flexible strain
relief portion (not shown) to minimize strain on the subcutaneous
sensor set 10 and prevent movement of the implanted sensor 12,
which can lead to discomfort or dislodging of the analyte sensor
set 10. The flexible strain relief portion is intended to minimize
sensor artifacts generated by user movements that causes the
subcutaneous analyte sensor set 10 to move relative to the
Holter-type recorder 100.
The interface of the Holter-type recorder 100 connects with the
cable 102 that is connected with the subcutaneous sensor set 10. In
preferred embodiments, the sensor interface is permanently
connected to the cable 102. However, in alternative embodiments,
the sensor interface may be configured in the form of a jack to
accept different types of cables that provide adaptability of the
Holter-type recorder 100 to work with different types of
subcutaneous analyte sensors and/or analyte sensors placed in
different locations of the user's body. In preferred embodiments,
the printed circuit board 108, and associated electronics, are
capable of operating in a temperature range of 0.degree. C. and
50.degree. C. However, larger or smaller temperature ranges may be
used.
Preferably, the battery assembly will use a weld tab design to
connect power to the system. For example, it can use three series
silver oxide 357 battery cells 110, or the like. However, it is
understood that different battery chemistries may be used, such as
lithium, alkaline or the like, and different numbers of batteries
can be used. In further embodiments, the sensor interface will
include circuitry and/or a mechanism for detecting connection to
the subcutaneous analyte sensor set 10. This would provide the
capability to save power and to more quickly and efficiently start
initialization of the subcutaneous analyte sensor set 10. In
preferred embodiments, the batteries 110 have a life in the range
of 2 weeks to 2 years, and provide a low battery warning alarm.
Alternative embodiments may provide longer or shorter battery
lifetimes, or include a power port or solar cells to permit
recharging of the batteries 110 in the Holter-type recorder
100.
In preferred embodiments, the Holter-type recorder 100 provides
power, through the cable 102 and cable connector 104 to the analyte
sensor set 10. The power is used to drive the analyte sensor set
10. The power connection is also used to speed the initialization
of the sensor 12, when it is first placed under the skin. The use
of an initialization process can reduce the time for sensor 12
stabilization from several hours to an hour or less. The preferred
initialization procedure uses a two step process. First, a high
voltage (preferably between 1.0-1.2 volts--although other voltages
may be used) is applied to the sensor 12 for 1 to 2 minutes
(although different time periods may be used) to allow the sensor
12 to stabilize. Then, a lower voltage (preferably between 0.5-0.6
volts--although other voltages may be used) is applied for the
remainder of the initialization process (typically 58 minutes or
less). Other stabilization/initialization procedures using
differing currents, currents and voltages, different numbers of
steps, or the like, may be used. Other embodiments may omit the
initialization/stabilization process, if not required by the
analyte sensor or if timing is not a factor.
At the completion of the stabilizing process, an initial reading
may be downloaded from the analyte sensor set 10 and the
Holter-type recorder 100 to the data processor 200, computer,
communication station, or the like, to verify proper operation of
the analyte sensor 10 and the Holter-type recorder 100. In
alternative embodiments, a fluid containing a known value of
glucose may be injected into the site around the analyte sensor set
10, and then the Holter-type recorder 100 records the data for the
known value to provide a reference point to the recorded data.
During the calibration process, the Holter-type recorder 100 checks
to determine if the analyte sensor set 10 is still connected. If
the analyte sensor set 10 is no longer connected, the Holter-type
recorder 100 will abort the stabilization process and sound an
alarm (or flash a light, or download a signal to the data processor
200, computer, communication station, or the like, to sound an
alarm).
Additional embodiments of the Holter-type recording device may
include an alarm, such as a piezo element, or the like, that will
notify of an alarm or error condition. The piezo element may also
be used to transmit data by hyper-audio frequencies.
In further alternative embodiments, the Holter-type recorder 100
can be combined with a analyte sensor set 10 as a single unit. This
would be particularly well adapted where batteries and the recorder
can be made cheaply enough to facilitate changing the Holter-type
recorder 100 with each new analyte sensor set 10.
As shown in FIG. 2, the data processor 200, computer, communication
station, or the like, may include a display 214 that is used to
display the results of the measurement received from the sensing
portion 18 in the analyte sensor set 10 received via a download
from the Holter-type recorder 100. The results and information
displayed includes, but is not limited to, trending information of
the characteristic (e.g., rate of change of glucose), graphs of
historical data, average characteristic levels (e.g., glucose), or
the like. The display may be used to show glucose meter (or
calibration) data. Alternative embodiments include the ability to
scroll through the data. The display 214 may also be used with
buttons (not shown) on the data processor 200, computer,
communication station, or the like, characteristic monitor to
program or update data in the data processor 200.
In further embodiments of the present invention, the data processor
200, computer, communication station, or the like, may be replaced
by a different device. For example, in one embodiment, the
Holter-type recorder 100 communicates with an RF programmer (not
shown) that is also used to program and obtain data from an
infusion pump or the like. The RF programmer may also be used to
update and program the recorder 100, if the recorder 100 includes a
receiver for remote programming, calibration or data receipt. The
RF programmer can be used to store data obtained from the sensing
portion 18 and then provide it to either an infusion pump,
characteristic monitor, computer or the like for analysis. In
further embodiments, the recorder 100 may transmit the data to a
medication delivery device, such as an infusion pump or the like,
as part of a closed loop system. This would allow the medication
delivery device to compare sensor results with medication delivery
data and either sound alarms when appropriate or suggest
corrections to the medication delivery regimen. In preferred
embodiments, the recorder 100 would include a transmitter to
receive updates or requests for additional sensor data. An example
of one type of RF programmer can be found in U.S. patent
application Ser. No. 60/096,994 filed Aug. 18, 1998 and is entitled
"INFUSION DEVICE WITH REMOTE PROGRAMMING, CARBOHYDRATE CALCULATOR
AND/OR VIBRATION ALARM CAPABILITIES," which is herein incorporated
by reference.
In use, the implantable analyte sensor set 10 permits quick and
easy subcutaneous placement of the sensing portion 18 at a selected
site within the body of the user. More specifically, the peel-off
strip 34 (see FIG. 1) is removed from the mounting base 30, at
which time the mounting base 30 can be pressed onto and seated upon
the patient's skin. During this step, the insertion needle 14
pierces the user's skin and carries the protective cannula 16 with
the sensing portion 18 to the appropriate subcutaneous placement
site. During insertion, the cannula 16 provides a stable support
and guide structure to carry the flexible sensor 12 to the desired
placement site. When the sensor 12 is subcutaneously placed, with
the mounting base 30 seated upon the user's skin, the insertion
needle 14 can be slidably withdrawn from the user. During this
withdrawal step, the insertion needle 14 slides over the first
portion 48 of the protective cannula 16, leaving the sensing
portion 18 with electrodes 20 directly exposed to the user's bodily
fluids via the window 22. Further description of the needle 14 and
the sensor set 10 are found in U.S. Pat. No. 5,586,553, entitled
"TRANSCUTANEOUS SENSOR INSERTION SET"; co-pending U.S. patent
application Ser. No. 08/871,831, entitled `DISPOSABLE SENSOR
INSERTION ASSEMBLY"; and co-pending U.S. patent application Ser.
No. 09/161,128, filed Sep. 25, 1998, entitled "A SUBCUTANEOUS
IMPLANTABLE SENSOR SET HAVING THE CAPABILITY TO REMOVE OR DELIVER
FLUIDS TO AN INSERTION SITE," which are herein incorporated by
reference.
Next, the user connects the connection portion 24 of the sensor set
10 to the cable 102 of the Holter-type recorder 100, so that the
sensor 12 can then be used over a prolonged period of time for
taking blood chemistry or characteristic readings, such as blood
glucose readings in a diabetic patient. Preferred embodiments of
the Holter-type recorder 100 detect the connection of the sensor 12
to activate the Holter-type recorder 100. For instance, connection
of the sensor 12 may activate a switch or close a circuit to turn
the Holter-type recorder 100 on. The use of a connection detection
provides the capability to maximize the battery and shelf life of
the Holter-type recorder prior to use, such as during
manufacturing, test and storage. Alternative embodiments of the
present invention may utilize an on/off switch (or button) on the
Holter-type recorder 100.
The recorder 100 is then affixed to the user's body with an
adhesive overdressing. Alternatively, the peel-off strip 34 (see
FIG. 1) is removed from the lower case 116, at which time the lower
case 116 can be pressed onto and seated upon the patient's skin.
The user then activates the recorder 100, or the recorder is
activated by detection of the connection to the sensor 12 of the
analyte sensor set 10. Generally, the act of connecting (and
disconnecting) the sensor 12 activates (and deactivates) the
Holter-type recorder 100, and no other interface is required. In
alternative steps, the analyte sensor set 10 is connected to the
recorder 100 prior to placement of the sensor 12 to avoid possible
movement or dislodging of the sensor 12 during attachment of the
recorder 100. Also, the recorder may be attached to the user prior
to attaching the sensor set 10 to the recorder 100.
The user then verifies proper operation of the recorder 100. Thus,
once a user attaches a recorder 100 to an analyte sensor set 10,
the sensor 12 is automatically initialized and readings are
periodically recorded, together with other information, in the
Holter-type recorder 100.
After an analyte sensor set 10 has been used for a period of time,
it is replaced. The user will disconnect the analyte sensor set 10
from the cable 102 of the Holter-type recorder 100. In preferred
embodiments, if additional measurements are required and/or
desired, the Holter-type recorder 100 is removed and positioned
adjacent the new site for a new analyte sensor set 10. In
alternative embodiments, the user does not need to remove the
recorder 100. A new analyte sensor set 10 and sensor 12 are
attached to the Holter-type recorder 100 and connected to the
user's body. Recording then continues, as with the previous sensor
12. If the user must replace the Holter-type recorder 100, the user
disconnects the Holter-type recorder 100 from the analyte sensor
set 10 and the user's body. Finally, the data stored in the memory
112 of the Holter-type recorder 100 is downloaded (or transmitted)
to the data processor 200, computer, communication station, or the
like, for analysis and review.
Additional embodiments of the present invention may include a
vibrator alarm (or optical indicator such as an L.E.D.) in the
Holter-type recorder 100 to provide a tactile (vibration) alarm to
the user, so as to indicate an analyte sensor set 10 malfunction,
improper connection, low battery, missed message, bad data,
interference, or the like. The use of a vibration alarm provides
additional reminders to an audio alarm, which could be important
with someone suffering an acute reaction, or to have non-audio
alarms to preserve and conceal the presence of the Holter-type
recorder 100.
FIGS. 8 and 9 show a Holter-type recorder 300 in accordance with
another embodiment of the present invention. In the illustrated
embodiment, the analyte sensor 10 is connected, via a cable (or
connector) 102, to a signal conditioning circuit 302, such as a
potentiostat or the like, in a housing 304 of the Holter-type
recorder 300. The signal conditioning circuit 302 is in turn
connected to a current to frequency converter (I to F) 306. The
output of the I to F 306 is a digital frequency that varies as a
function of the sensor signal produced by the analyte sensor 10. In
alternative embodiments, other signals, such as voltage, or the
like, may be converted to frequency. The digital frequency is then
counted by a digital counter, and the digital counter 310 value is
periodically read and stored with an indication of relative time,
by a microprocessor 310, into a non-volatile memory 312. When the
monitoring period is over, the data is downloaded from the
Holter-type recorder 300 by activating a reed switch 314. In
preferred embodiments, the reed switch 314 is activated by a magnet
400 (see FIG. 9). However, in alternative embodiments, a stylus
activated switch, a code transmitted to the Holter-type recorder, a
manual switch, or the like, may be used. Once the reed switch 314
is closed, the Holter-type recorder 300 begins downloading the
stored data by driving an LED 316 at a data rate until all of the
stored data and relative time indications are transmitted to a
receiver and processing device, such as a computer, laptop, PC,
communication station, or the like. In alternative embodiments, a
wired connection, ultrasonic frequencies, optical, RF or other
transmission protocol may be used. In preferred embodiments, the
stored data is maintained in the non-volatile memory 312 until
confirmation of the successful download is received by the
Holter-type recorder 300. In alternative embodiments, an additional
switch must be activated to delete the stored data, or the
Holter-type recorder is cleared using an on-board program that
clears the memory after a predetermined period of time. The
Holter-type recorder 300 also includes a power source 322 and a
power management circuit 324 to power the Holter-type recorder
300.
While the description above refers to particular embodiments of the
present invention, it will be understood that many modifications
may be made without departing from the spirit thereof. The
accompanying claims are intended to cover such modifications as
would fall within the true scope and spirit of the present
invention.
The presently disclosed embodiments are therefore to be considered
in all respects as illustrative and not restrictive, the scope of
the invention being indicated by the appended claims, rather than
the foregoing description, and all changes which come within the
meaning and range of equivalency of the claims are therefore
intended to be embraced therein.
* * * * *